gpu: nvgpu: Add LDIV slowdown factor in INIT cmd.

PMU ucode is updated to include LDIV slowdown factor in gr_init_param command.
- Defined a new version gr_init_param_v2.
- Updated the PMU FW version code.
- Set the LDIV slowdown factor to 0x1e by default.
- Added sysfs entry to program ldiv_slowdown factor at runtime.

Bug 200391931

Change-Id: Ic66049588c3b20e934faff3f29283f66c30303e4
Signed-off-by: Deepak Goyal <dgoyal@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1674208
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/common/linux/platform_gk20a.h

@@ -74,6 +74,9 @@ struct gk20a_platform {
 	/* Delay before rail gated */
 	int railgate_delay_init;
 
+	/* init value for slowdown factor */
+	u8 ldiv_slowdown_factor_init;
+
 	/* Second Level Clock Gating: true = enable false = disable */
 	bool enable_slcg;